Sheet-retaining attachment for platen presses



Feb. 27, 1945. H. L. THOMPSON 2,370,591

sHEET-RETAINING ATTACHMENTS FOR-LATEN PRESSES Filed May 6,. 1943 2 Sheets-Sheet l FIG. Vz2.. G

e sa B, a5 A -ATTORNEYS- Feb. 27, 1945. i H. l.. THOMPSON 2,370,591

SHEET-RETAINING ATTACHMENTS FOR PLATEN PRESSES Filed May 6, 1943 2. Sheets-Sheet 2 F IG; 6.

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INVENTOR HELFFB L. Thmmpcn-L v k ATTORNEYS.

Patented Feb. 27, 1945 UNITED SHEET-RETAINING ATTACHMENT v PLATE-N messias Fon.y

Harry L. Thompson,r Cooperstown, N. Dak. vpplication May 6, 1943,*Serial No.4`85f899 miams.' (01.101408) This invention relates to printing and more specifically to work-engaging members, adapted to prevent flip-up of the sheet after the printing impression is made.

An important object of the invention is to provide an attachment for the tympan ofplaten presses, either automatic or hand-fed, adapted to prevent raising of the printe'd sheet from the platen between the Vrelease of the grippers and until the platen has reached its downward limit of movement. Ordinarily, there is an arcuate movement of about 60 degrees in the lastvportion of thedescent of the platen during which the lgrippers do not follour the platen and it is during this portion of descent that the printed sheets alteration' of conventional tympanother than providing two perforations therein for each attachment) which may be operatedveither Aby the grippers or by the furniture, as preferred, thus enabling one of two diierent means' to actuate the attachment.y f

Other objects and advantages of; 'the invention will be apparent during the course of the following detailed description, taken in connection with the accompanying drawings, and in which drawingsf Figure 1 is a-plan view of two of the attachments with a sheet, in positionzto be'printed.

Figure 2 is a. longitudinal section ofa tympan and furniture, with the latter engaged in operating the attachments.

Figure 3 -is a view similar to Figure l but showing the position of parts after the sheethas been printed. y

yFigure 4 is an enlarged fragmentary view-showing gripper operation of the attachment, as disf tinguished from the furniture operation'of Fig# ures 1*-3 inclusive. y 3" Figure 5 is 'an enlarged top plan View ofjthe attachment. 1 I 'Y f Figures 6, 7 and 8 are vertical sections substantially upon their respectivelines of Figure.

Figure 9 is a vertical section'substantially upon VIliigurel is an elevation of a handle member and :Figure 11 an elevationof a portion of .an arml and-'fingen and'vertical section of a stop, employed in :the 4operation of the-novel attachment.

In thedrawings wherein for the purpose of illustration is shown a. preferred embodiment of the invention and'wherein similar reference characters designate corresponding parts thruout the several views, theletter A may designate generallyga platen printing' press, B the novel attachments and C a sheet of material being operated upon. f

vThe portion of platen printing press A shown is of conventional construction and includes a platen and associated tympan I5', having an upper sheet-supporting surface or Aface I6 and lower face |68, and thru which, from face to face, are two'pairs of spaced-'apart perforations -l l which will be referred to later. The press also includes grippers I8, gripper fingers I9 attached thereto, a tympan gauge 20 anda suitable number of gauges or guides 21|. a portion of furniture 22. Y

As for the novel attachment B, the same includes a combined base and support 25, substantially L-shaped in verticalA transverseI section, as shown in Figure A8, having a flat vhorizontal baseportion 26 and aat vertical upright portion 21 at one end 28 of the base portion. This base and support 25 may comprise a sheet of suitable material formed into the L-shape.

` Extending from the edge 29 of the base portion 26,inwardly toward theend 28 is one or more spaced-apart slots ll'ptoprovide for adjustment in twodirections of theattachment B. The base There is also shown -portion '26S may be provided, also, with a pair of spaced-'apart bearings 3| which may be formedV by'slitting thru the portion 26 (forming two pairs of paralleling slits) and upsetting the material between eachy pair, to form/eyes for a portion of the attachment latertobe described.

yThe'upright portion .21 may be provided with two perforationsg32 and `33, 'each for a different purpose, to be described. These may be relatively close to the upper ed'ge 34 of the portion 21 and spaced apart.

Means is provided adapted to project close to the platen ISand, beneath the sheet C (before the latter iseimpressed' and While the platen is ascending), and" adjacent an edge or opposite edges of-v the sheetk C, to be moved from beneath the sheet 'as'-'the-sheet is being. impressed, and

to be moved-:toproject over 'this edge or edges of the sheetjand above and close to the sheet during end extending thru the the time or period the platen is descending particularly after release of the sheet by the gripbeslidable in the perforation 32, to extend from each face of the upright portion 21. 'I 'hismember 35 is adapted tobepositioned vsubstantially horizontally and to parallelthe upper face I6.

Means is provided to either be engaged by theV v grippers I8 or furniture 22 and to be operatively connected with the member or `finger 35 to move the same into the various positions heretofore described. This latter means preferably comy prises a length ofv suitable material, as heavy,

rigid wire, formed into a normallyy upwardly-4 extending, somewhat bowed lever 38, shownvparticularly in Figures 7 and 1U, an eye 39 on the lever,` near its lower end 4D a horizontal, s'ubstantially straight portion 4| extending across the upper faceof the basetportion 26 andthru the bearings 3| and terminating in an upwardlyextending arm 42 ending in an eye 43. Thru this eye 4-3 and the eye. 36 in the member or finger 35 may extend a suitable pivot pin 44, pivotally coupling the .two together. Of course whenfassembled, the member or finger 35 projects in one direction (toward and thru the upright portion 21 from the eye 43) and the lever 38 projects in the opposite direction, so that depression of the lever will retract the free end of theiinger 35 toward the upright portion 21, as is now apparent i Means for limiting movement of the finger or member35 in one direction, i. e., outwardly of the upright portion 21, isprovided, and may comprise a suitable stop 45, provided with a recessed or forked portion 46 engaging the arm 42 at that portion of the` arm facing the upright portion 21. A suitablescrew41 mayibe provided sheet feeding apparatus will place an unimpressed sheet in the position shown in Figure l, with the sheet C resting upon the lingers 35,.and this will be the position of the sheet C .while the platen rises but when the furniture, grippers, or grip- `per fingers contact the levers 38 and depress them, the lingers 35 will be retracted `as in Figures 2 and 5 and the sheet edges, supported upon the fingers, will contact the platen as in Figure 2.

As the furniture or grippers release the levers 38, the fingers 35 will again move to their initial position but, this time, theywill be over the sheet C andclose adjacent its upper face, and will ref main in this position even after the grippers have to secure this stop to the base portion 26, as

in Figure 1l.

Means for moving the `lever 38,110 a substan-k tially upright position, after release by the furniture or grippers of the press A, may comprise a retractable coil spring50, with one end extending thru the eye`39 of the lever 38 and the other perforation 33 of the upright portion 21.

Means for securing the attachment B-to the press in an adjustable` position mayA comprise a suitable. number of bolts 55, with their heads 5t contacting the. upper face of the base portion 21, their vShanks v.51.extending thru the slots 38 and perforation |1, with suitable nuts 58 for the ends of the Shanks 51,-projecting beloW the tympan' I5, as shown particularly in Figure 6. f Y

Ordinarily two attachments B are employed on each press A, and :may be positioned as shown in Figures 1 and 3, .close vadjacent opposite end edges 80 of the sheet C, so `that the lingers or members 35 will normally ybe within the vertical planes of these end edgesfBU, but ,when retracted, the lingers will clear the edges 60 and be outside these planes. Positioned as shown'in Figures 1 and 3, the lever 38 will be engaged by the furniture 22, but if the grippers I8 or their fingers I9 fare moved, as is well known in the art, either may engage the lever38 and `move it to the dotted line position of Figure 7 during rising ofithe platen. It is now apparent that a press feeder or the released their hold upon the sheet. As a result,

the sheet will not iiip up, even When released by the grippers but the retaining effect of the iingers 35 will not prevent easy removal of the printed sheet and the lingers 35 are again in position to receive the edge portions of a fresh sheet.

Thus, it vwill `be seen that thev novel attachment takes over substantially the `function's of the grippers and gripper fingers, particularly after the grippers and fingers have released the f sheet, and the attachments will restrain the sheet against movement away from the platen during the whole period of its descent, yet the sheet is not retained so tightly that it cannot be removed when desired, and the attachments interfere in no way with the-functions of the guides 2| and tympan gauge 28, nor with the making ofthe impression.

Various changes may be made to the form of the invention herein shown and described withoutdeparting from the spirit of the invention or I a normally vupwardly-extending arm pivotally connected with said member; means to engage, and be depressed by, a movable portion of said press, comprising a normally upright lever, operatively connected with said arm; an `L-shaped combined horizontal base and upright support for said member, arm and lever, with said lever pivoted in said base and. said member slidably carried `by and normallyv projecting beyond said support; means limiting movement of said member in one direction; and means for moving said lever to an upright position after release of said lever by said movable portion of. said press.

2..'In a sheet v'supporting means and a holddownfdevice for a platen printing press, adapted Ato retain a printed sheet against flip-up, after release by grippersL and gripper fingers', during the entire time of the descent 'of the platen, a movable member, including a rigid ngerv having a straight, forward end, substantially paralleling the sheet-supporting surface of said platen at all times and having a sheet-Supporting upper surface,` means to reciprocatesaid member, including an arm operatively connected with said member; and a normally upright lever, operatively connected with said arm and disposed within the downward path of travel of a movable portion of said press; an'L-shaped combined base and support for said member, arm"` and lever, with said lever pivotedin said base and said member extending thru and beyond said support; means limiting movement of said member inr one direction; and means for moving said lever to an upright position after release of said lever by said movable position of said press.

3. In a sheet-supporting means and a holddown device for a platen printing press, adapted to retain a printed sheet against flip-up, after release by grippers and gripper fingers, during the entire time of the descent of the p1aten,'a movable member, including a rigid finger, having a straight forward end movable in a plane substantially parallelingr the sheet-supporting surface of said platen and having a sheet supporting upper surface; means to reciprocate said iinger, including a normally vertically disposed arm operatively connected with said member and comprising a normally upright lever, connected with said arm and disposed within the downward path of travel of a movable portion of said press; an L-shaped combined base and support for said member, arm and lever, with said lever pivoted in said base and said member extending thru said f support with its forward end normally projecting beyond the outer face of said support; means limiting movement of said member in one direction so that said free end will be retracted, comprising a stop for said arm; and means for movling said lever to an upright position after release of said lever by said movable portion of said press.

4. On a sheet hold-down. device for a platen printing press, adapted to retain a printed sheet against flip-up, after release by a gripper and gripper fingers, during the entire ltime of the descent of the platen, and then release saidA sheet, a base; an upright support wall extending from said base and having an outer face and a horizontally-disposed perforation, a rigid finger, with its longitudinal axis normal to the path of travel of said gripper, slidable through said perforation with its free end normally extending beyond saidl vouter face, a normally upright arm pivotally connected to the other end of said finger, a straight horizontal portion secured at one end to the lower end of said arm, bearings for said portion carried by said base, a lever secured to the other end of said portion, extending upwardly from said base and disposed transversely to and in the path of travel of said gripper and means normally urging said lever upwardly, comprising a retraction spring,` secured at one end to said upright support and at its other end to said base.

HARRY L. THOMPSON. 

